With all of the discussion lately about using a Helix or a Cassette/Car Barge I would like to discus the advantage or disadvantages of both.
#1 The Helix
A helix seems at first glance to be the easiest to plan.
Not really, first you must plan on the radius and rise or fall.
How small of a radius can you live with or how big does it need to be?
What is the grade of the helix?
With an 18"dia radius and a rise of 4" the resulting grade would be over 7%. 3.5%
While it would seems a simple thing to have your loco going up a 18" radius helix (HO scale) you must take into account the number of cars you intend to take up grade behind your loco. Add in a 2% grade increase for the curve and the grade seems more like 9% 5.5% now.
For a 2.6% grade you would need a run of 153.84", divided by 3.14 yields a radius diameter of 48.99" (inches) with a resulting floor space requirement of about 100"x100" 50"x50" for the helix.
#2 The Cassette/Car Barge
A cassette/car barge while it seems unrealistic, it takes up must less space. A cassette of 50" by 4" wide only takes up the space of 50" by 4" on each level of your layout. You need only to make a docking port (support) on both levels for the cassette. The cassette can be as long as you can comfortably handle or a short as your longest car. You can make multiple cassettes or just one. You can make a rack for storage of the cassettes and use the multiple cassettes as off line staging or a fiddle yard. European model railroaders have been doing this for decades.
While a Cassette/Car Barge would require you to be more proactive in the hand
Beggin’ yer pardon, but I see a gaping hole in your math! The circumference of a circle is TWICE the radius multiplied by Pi. With 4" vertical spacing between railheads, your 18" radius helix has a grade of less than 4%. If your helix roadbed is thin enough, you could get away with as little as a 3% grade. Your second equation solves to very close to a 24" radius, not 48" plus.
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#2 The Cassette/Car Barge
A cassette/car barge while it seems unrealistic, it takes up must less space. A cassette of 50" by 4" wide only takes up the space of 50" by 4" on each level of your layout. You need only to make a docking port (support) on both levels for the cassette. The cassette can be as long as you can comfortably handle or a short as your longest car. You can make multiple cassett
Helix: takes up a lot of space on each level that can’t be used for anything else. But train length is not limited. Rolling stock does not have to be handled by 0-5-0. Human error results in fewer floor dives.
A helix is a pretty good solution where the space it takes is 20% or less of the layout floor space (my minimum rule of thumb). Works for medium size and larger layouts.
Cassette/car barge/train elevator: May take a lot less space, but:
train length is very limited. I find manually handling a cassette more than 36-40" long is very awkward. Even in N, that’s a short train. An elevator can be longer, but now the train can’t be turned easily.
there are many more opportunities for unintentional floor diving compared to a well done helix.
Ensuring device (cassette/ferry/elevator) is level and properly aligned so that train can enter/depart at each stop is not trivial. Doable, but not trivial.
My opinion is that cassettes and barges work very well with small layouts - where the space a helix takes is problematic - and as an interchange on larger layouts.
Each solution has its place, and situations that maximize its strengths and minimize its weaknesses. The key is to recognize your particular situation, and pick the more appropriate solution.
I view a car barge as something very different from a cassette, although physically they are pretty similar. To me, a cassette is purely for operational convenience - it’s a way to introduce trains on to a layout. A car barge, however, is a model of a prototype operation - loading and unloading cars from a ferry. The cassette would typically be a “hidden” activity, while the car barge would be part of the operation itself.
After one of our earlier discussions, I pulled up XTrakCad and started playing with a car barge terminal. I quickly discovered that it is far from a small-footprint operation. Assuming that the standard operating practice will, at least sometimes, involve unloading a full ferry and then reloading it with just as many cars, you need more storage space on land than you have on the ferry. You need to combine this with at least a few turnouts to get an idea of how much layout space would have to be devoted to an operational ferry terminal. I still think it would be an interesting “industry” on the layout, since you could combine it with spotting a few cars at local warehouses, and you can use pretty much any type of freight cars you’d like for “through” traffic.
If you have the room and the skills by all means using a helix is doable.
However if like me you are not willing to give up the space a helix needs then a cassette system may be for you.
As it was stated an elevator can do the same thing. I have drawn up plans for such a device. But as my layout is a single level at this point in time I have no need of either. And if I were to run a 20 car train it would be chasing its own tail or very close to it.
I am thinking of using a cassette as a way to have cars exit and reenter my layout without using the five finger crane or the hand of god to do it.
Should work just fine, as long as the cassette is of a reasonable length to handle.
I am building a layout now (The Warehouse District) where I plan to use a cassette for two purposes:
Bringing cuts of cars into or out of the layout (5 cars at a time) and
Functioning as a removable bridge across the entrance to the room
Like this:
Conceptually, my track plan is like this:
So the cassette is used to feed in cars either on the east end of the layout or the west end of the layout - depending on whether I bring cars clockwise (coming in from the east) or counterclockwise (coming in from the west).
I would have preferred a staging yard reachable by helix where I could have prestaged 3-4 10-12 car complete trains set to arrive from the east and 3-4 10-12 car trains set to arriving from the west without any fiddling during an operating session.
But I can very easily live with having to feed in or take out five cars at a time using the cassette to transfer cars between the layout and four or five parallell 10-car staging tracks on a shelf above my layout.
I was doing some “thinking outside the box,” which is usually what happens when I’m “thinking on the pot,” but I wondered if anyone had used a rollaround cart to implement cassette staging. Think of a hospital gurney, but replace the patient with a set of parallel tracks and trains. The large 360-degree casters would allow the whole thing to be wheeled in and out of place, and you could even select which track would be accessed by pushing it a few inches.
Yes, it would be tricky to get the alignment right every time, but a clever “docking” system could be devised.
If you had a really fancy gurney, like the ones they have on ambulances, you could even lower it down a foot or so and tuck it under another part of the layout when not in use. Or, take it out to the kitchen and return with refreshments for your crew.
My current layout actually started out as an 18" circle on a 3/4 inch plywood top sitting on top of a Rubbermaid cart. (Thomas the Tank Engine for the grandchildren).
After I built real benchwork I thought about using it as a roll around casette, but decided against it. I remain, however, convinced that it would work, and they are available in narrow widths like they use in the aisles of airliners.
I wish I could remember the link but I recall a case recently where an elevator was used to move trains to an upper level rather then a helix. It took little space and seemed to work pretty well. If I can find a link or reference I will post it back here.
There was a layout in an early 90s MR that featured car ferries on carts that would but up against specially keyed ferry docks on the layout to allow cars to be moved on and off the layout just as you describe. I wish I could remember the which issue, now its gonna bug me… it was pretty nifty.
No, thats pretty nifty, but this was a home built unit I am thinking of.The guy showed how he built it. Unfortunately I came across it before I started organizing my links and synching them with foxmarks, so I can’t find it now.
Mr B, I can’t remember the modeler’s name but there was somebody, many moons ago, who had a Great Lakes type car ferry mounted on a tea caddy. I don’t know how he aligned it with the apron, but this is a logical place for a working, hinged bridge.
An unpowered watercraft with railroad tracks on it is usually referred to as a car float. Barges usually carry bulk cargo.
The topography of the area I model is not conducive to modeling car ferries or floats - think West Virginia. My permanent cassette interface is part of my hidden staging, not part of the modeled scenery.
I will be using a train elevator to complete the loop for my unit coal train ‘empties in, loads out’ (at the colliery) operation. It has to connect the colliery (the highest trackage on the layout) with Down staging (AKA Takada) deep inside the mountain. John Armstrong’s ‘dehydrated canal lock’ is my design inspiration.
